Mail Archives: djgpp/2003/01/09/06:30:12
On Wed, 8 Jan 2003 15:58:30 +0000 (UTC), "Joel Saunders"
<jbs30000 AT aol DOT com> wrote:
>I made a post about this yesterday, but it never showed up, so I'll try
>again, and hope it posts this time.
usenet posts take time to propagate around the world and replies
take time to propagate back to you -- especially if you have a
cheap ISP -- you may not even get to see all of your replies --
be patient -- check to see if google shows you have any replies
-- you already had two replies that I can see before you reposted
>For a basic bmp loader I made, the struct to hold the bmp header doesn't
>work. I used __attribute__((__packed__)) after each item, but it's no
>good. I gave the file for the program, a C extention, instead of a cpp
>extention, so I know that probably makes some difference.
>Here's the header...
>struct BMP_Header {
> unsigned int BM __attribute__((__packed__));
> unsigned long File_Size __attribute__((__packed__));
> unsigned int R_1 __attribute__((__packed__)); // Reserved 1
> unsigned int R_2 __attribute__((__packed__)); // Reserved 2
> unsigned long BMP_Offset __attribute__((__packed__));
> unsigned long Header_Info __attribute__((__packed__));
> unsigned long BMP_Width __attribute__((__packed__));
> unsigned long BMP_Height __attribute__((__packed__));
> unsigned int BMP_Planes __attribute__((__packed__));
> unsigned int BPP __attribute__((__packed__));
> unsigned long Compression __attribute__((__packed__));
> unsigned long BMP_Size __attribute__((__packed__));
> unsigned long Width_PPM __attribute__((__packed__));
> unsigned long Height_PPM __attribute__((__packed__));
> unsigned long Num_of_Colors __attribute__((__packed__));
> unsigned long Important_Colors __attribute__((__packed__));
>}image;
>Here's what I had to use instead of the header:
>unsigned char image[54];
>#define image_BM ((int *)&image[0])[0]
>#define image_File_Size ((long *)&image[2])[0]
>#define image_R_1 ((int *)&image[6])[0]
>#define image_R_2 ((int *)&image[8])[0]
>#define image_BMP_Offset ((long *)&image[10])[0]
>#define image_Header_Info ((long *)&image[14])[0]
>#define image_BMP_Width ((long *)&image[18])[0]
>#define image_BMP_Height ((long *)&image[22])[0]
>#define image_BMP_Planes ((int *)&image[26])[0]
>#define image_BPP ((int *)&image[28])[0]
>#define image_Compression ((long *)&image[30])[0]
>#define image_BMP_Size ((long *)&image[34])[0]
>#define image_Width_PPM ((long *)&image[38])[0]
>#define image_Height_PPM ((long *)&image[42])[0]
>#define image_Num_of_Colors ((long *)&image[46])[0]
>#define image_Important_Colors ((long *)&image[50])[0]
>What can I do to make the struct work?
use short instead of int for now, until you can use int16_t (C99)
Thanks. Take care, Brian Inglis Calgary, Alberta, Canada
--
Brian DOT Inglis AT CSi DOT com (Brian dot Inglis at SystematicSw dot ab dot ca)
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